* sys/netinet/in_gif.c, sys/netinet6/in6_gif.c: drop IFF_LINK0   (multi destination mode) support.
* sys/netinet/in_gif.c, sys/netinet6/in6_gif.c: drop IFF_LINK0
  (multi destination mode) support.

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame